Punch and punch-holder.



W. C. DESMOND.

PUNCH AND PUNCH HOLDER.

APPLICATION FILED DEC.26.1911- Patented Janj14,1919.

IN VEN TOR: fiiz. Gas. iii-51402 17, BY 1 A,

I RNEYS.

WITNESSES: Mm.

ATTO

WILLIAM CHARLES DESIVIOND, OF WOODLAWN, ILLINOIS.

PUNCH AND PUNCH-HOLDER.

Specification of Letters Patent.

Patented Jan. 14, 1919.

Application filed December 26. 1917. Serial No. 208,842. I

To all whom it may concern:

Be it known that I, WILLIAM CHARLES DESMOND, a citizen of the United States, and a resident of Woodlawn, in the city of Chicago, county of Cook, and State of Illlnois, have invented certain new and useful Improvements in Punches and Punch-Holders; and I do hereby declare that the following description of my said mventron, taken in connection with the accompanying sheet of drawings, forms a full, clear, and exact-specification, which will enable others skilled in the art to which it appertains to make and use the same.

This invention has general reference to punches and holders therefor adapted to be applied to suitable punch presses for the punching of rivet holes in structural material of all kinds, and it consists, essentially, in the novel and peculiar combination of parts and details of construction, as hereinafter first fully set forth and described and then pointed out in the claim.

In the sheet of drawings already referred to, which serves to disclose my invention more fully, Figure 1 is an elevation of my invention. Fig. 2 is a cross section in line ()O of Fig. 1. Fig. 8 is a bottom plan thereof, and, Fig. 4, an elevation of the punch itself.

Like parts are indicated by corresponding symbolsand character of reference 1n all the figures of the drawing.

Punches for punching rivet holes in plates, bars, and structural shapes of all kinds are now produced from round tool steel with a large, circular, flat head of a diameter approximating twice the diameter of the hole to be punched. Below this head, the stock is machined down to a diameter about one-half inch less than that of said head, which portion extends for perhaps an inch and is then gradually reduced in diameter toward the lower end to the size of the hole to be punched. For instance, a punch for a five-eighth inch rivet is elevensixteenths of an inch in diameter at the lower end or cutting edge, and remains so for about one inch; then increases to fifteen-sixteenths inch in a taper or hollow curve for one-half inch, and then is straight at the latter diameter for three-quarters of an inch. Above this is the head, which is one-quarter inch thick and one and threeeighths inches diameter. Thus this punch 1s made from a cylindrical blank of one and three-eighths inches diameter and two and one-half inches long. The labor-cost of producing this punch in the lathe and the loss of the material removed makes these punches very expensive. Then, in the tempering of the same, a percentage of loss is sustained in temper-cracks in the corners under the heads, which renders such punches useless even before they have been put into service. In use these punches are dropped into and are projecting beyond an internally threaded sleeve, with the head bearing upon an internal shoulder in said sleeve. This sleeve is screwed upon a threaded shank on the slide of a punch press, with the said head of the punch rigidly held between the end of the said hank and the internal shoulder in the sleeve. It frequently happens that punches are changed from one size to another, and in making this change, chips of steel often find lodgment between the head of the punch and the internal shoulder, so that when the sleeve is screwed home on the shank, the punch is forced to assume a cant to one side, resulting in constant breakages of punches, the general life of which is the punching of about 8000 holes.

The aims of my invention are several fold; first, the production of a punchin which the labor cost of production may be greatly reduced, second, one in which a large proportion of tool steel now removed in the lathe, may be eliminated; third, one in which the loss of punches through temper cracks may be avoided, and, fourth, a punch of greatly increased life.

To better understand my invention, I now refer to the sheet of drawmg, in which A is the punch holder, consisting of a heavy metallic sleeve 1, having a hexagonal portion 2 at its upper, exterior extremity, by which the same may be rotated by a suitable wrench. Said sleeve terminates in a rounded lower portion 3. Interiorly of said sleeve, at the upper end thereof, there is produced an internal screw thread 4, adapted to engage an externally threaded shank 5, shown in dotted lines in Fig. 2, which shank is affixed to a slide of a suitable punch press (not shown). Belowscrew thread 4, the interior of said sleeve is inwardly tapered to form a tapered chamber 6, which chamber terminates in a circular opening 7, extending through the rounded portion 3 of the sleeve 1, to the exterior thereof.

B, in the drawing, represents the punch proper, made from tool steel, and having an upper straight part 8, in which there is formed a semi-circular groove 9, said punch gradually tapering down in diameter at 10, to the lower straight portion 11, which is of a diameter the equal of the holes to be punched, 12 being the cutting edge.

Into the groove 9 there is adapted to fit a wire ring 13, the ends 1 1 and 15 of which are normally maintained a short distance apart. This ring, when the ends are so spread apart, is quite a loose fit in said groove and is adapted to be squeezed together, so that when the same tightly embraces said groove, the ends 14: and 15 are almost in abutment.

The mode of application of my punch and punch holder may now be described as follows :Punch B is first dropped in punch holder A, with its lower end 11 projecting eXteriorly thereof through the opening 7, until the wire ring 13 impinges upon the wall of the chamber 6. Holder A is then screwed upon shank 5 until ring 13 has been forced into a tight embrace of groove 9. The punch is now tightly held from being withdrawn through hole 7, yet is not so immovably retained but that it may give a trifle in either direction when being stripped from the material punched. It is this slight resiliency, imparted or permitted by the ring 13 and its line contact with the interior chamber 6, allowing the punch to so give a trifle that is preventative of breakage of very many punches in a given run of work. As a fact there are records of from 40,000 to 412,000 holes punched by a single one of my improved punches.

addition to cost of labor saved in machining. Again the liability of loss through temper cracks is entirely eliminated.

I have heretofore described this invention with special reference to punches for fiveeighths of an inch holes, but it is obvious that my invention is applicable for almost every size hole, which it is'required to be punched; and that while this style of punches is especially well adapted for punching structural iron and steel, it is equally Well adapted for all kinds of Work and materials that can be done in a punching press.

Having thus fully described my invention, I claim as new and desire to secure to myself by Letters Patent of the United States A punch and punch holder, comprising a punch-press shank, said shank being exteriorly screw threaded, there being in the end of the punch shank an annular, flat recess, a hexagonal nut in screw-threaded engagement with said punch shank, said nut having in its bore a conical or tapering chamber, and a punch, said punch having a flat, cylindrical head engaging the annular recess in the end of the punch shank, said punch having an annular, semicircular, circumferential groove adjacent its end, and. an open, round-wire annular ring engaging said semicircular groove in said punch and the tapering chamber in said nut, to cause the contraction of said annular ring and to force the head of the punch'into the recess at the end of said punch shank when said nut is being rotated or screwed up, to compress said ring and to force it and the punch toward said punch-holder.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

WM. CHARLES DESMOND.

In the presence of WILLARD O. STARK, W. HARDING.

Copies of this patent may be obtained for five cents each, by addressing the Uommissioner; of Eatema Washington, D. G. 

